Sealing device

ABSTRACT

A sealing device includes a relatively dimensionally stable, elongated friction and/or wear element and an elastically-deformable elongated sealing element which rests lenghtwise on the friction and/or wear element. The friction and/or wear element encompasses the sealing element at the ends of the friction and/or wear element.

The invention relates to a sealing device having a relatively dimensionally stable, elongate friction and/or wear element and having an elastically deformable elongate sealing element, which rests lengthwise on the friction and/or wear element. The invention furthermore relates to a friction and/or wear element for a sealing device of this kind. The invention furthermore relates to a cam ring having a groove in which a sealing device of this kind is arranged. In addition, the invention relates to a variable displacement pump having a cam ring which can be moved in order to adjust the stroke of the variable displacement pump and which has a groove, and having a support ring.

The sealing element is embodied as an O-ring bead, for example, and, in addition to its sealing function, has the task of keeping the elongate friction and/or wear element in sealing contact with a mating surface. The friction and/or wear element is formed from a fluoroelastomer, for example. The sealing device is preferably used to seal a sealing gap between an adjustable cam ring and a support ring of a variable displacement pump of the kind known from European Patent Application EP 1 801 419 A2, for example.

It is an object of the invention to provide a sealing device having a relatively dimensionally stable, elongate friction and/or wear element and having an elastically deformable elongate sealing element, which rests lengthwise on the friction and/or wear element, by means of which sealing device leakage occurring in the installed state of the sealing device can be minimized and/or which sealing device is simple to assemble.

In the case of a sealing device having a relatively dimensionally stable, elongate friction and/or wear element and having an elastically deformable elongate sealing element, which rests lengthwise on the friction and/or wear element, the object is achieved by virtue of the fact that the friction and/or wear element encompasses the sealing element at the ends of said friction and/or wear element. This is a simple means of ensuring that, in the installed state of the sealing device, the sealing element has no contact at the ends thereof with mating surfaces, relative to which the sealing device moves during operation. Moreover, the embodiment according to the invention of the friction and/or wear element allows more precise guidance of the friction and/or wear element in the installed state of the sealing device. In the installed state, the sealing device is preferably arranged in a longitudinal groove in such a way that the friction and/or wear element projects somewhat from the longitudinal groove transversely to the longitudinal extent of the sealing device.

A preferred illustrative embodiment of the sealing device is characterized in that the friction and/or wear element is of substantially U-shaped design, having a base from which two legs are angled. Here, the base of the U-shaped form of the friction and/or wear element is significantly longer than the legs angled therefrom.

Another preferred illustrative embodiment of the sealing device is characterized in that the friction and/or wear element has an elongate main body with two angled ends. By means of the two angled ends, the friction and/or wear element encompasses the sealing element at the ends thereof. However, the ends of the sealing element are not completely encompassed by the angled ends of the friction and/or wear element in this arrangement.

Another preferred illustrative embodiment of the sealing device is characterized in that the elongate main body has a rectangular cross section. The cross section of the elongate main body is preferably matched to the groove width of a longitudinal groove in which the sealing device is arranged in the installed state. The distance between two groove flanks of the longitudinal groove is referred to as the groove width or groove breadth.

Another preferred illustrative embodiment of the sealing device is characterized in that the angled ends each have a rectangular cross section. The rectangular cross section of the angled ends is preferably matched to the groove width of a longitudinal groove in which the sealing device is arranged in the installed state. The distance between two groove flanks of the longitudinal groove is referred to as the groove width or groove breadth.

Another preferred illustrative embodiment of the sealing device is characterized in that the ends of the friction and/or wear element are each angled at a right angle to the elongate main body. If required, the angled ends of the friction and/or wear element can also be slightly beveled, thereby simplifying positioning where relevant.

Another preferred illustrative embodiment of the sealing device is characterized in that the sealing element is connected in a captive manner to the friction and/or wear element. The handling and installation of the sealing device are thereby considerably simplified.

Another preferred illustrative embodiment of the sealing device is characterized in that the sealing element rests by means of the ends thereof on the angled ends of the friction and/or wear element. The ends of the sealing element preferably rest flat against the angled ends of the friction and/or wear element.

Another preferred illustrative embodiment of the sealing device is characterized in that the sealing element is preloaded against the friction and/or wear element in the longitudinal direction. By means of the preload, the sealing element can be held captive on the friction and/or wear element in a simple manner.

Another preferred illustrative embodiment of the sealing device is characterized in that the sealing element is connected materially and/or positively to the friction and/or wear element at the ends of said sealing element. The sealing element can be secured on the friction and/or wear element by vulcanization, for example. It is particularly advantageous if the sealing device is embodied as a multicomponent injection molding with the sealing element and the friction and/or wear element.

Another preferred illustrative embodiment of the sealing device is characterized in that the friction and/or wear element is embodied as a sealing strip. The sealing strip is preferably formed from a fluoroelastomer.

Another preferred illustrative embodiment of the sealing device is characterized in that the sealing element is embodied as an O-ring bead. The sealing element is preferably produced from the same material as or a similar material to conventional O-rings.

The invention furthermore relates to a friction and/or wear element for a sealing device described above.

The invention furthermore relates to a cam ring having a groove in which a sealing device described above is arranged. The groove is preferably embodied as a longitudinal groove having a rectangular cross section.

In the case of a variable displacement pump having a cam ring which can be moved in order to adjust the stroke of the variable displacement pump and which has a groove, and having a support ring, the object indicated above is alternatively or additionally achieved by virtue of the fact that a sealing device as described above is arranged in the groove in such a way that the friction and/or wear element is held in contact with the support ring by a preload of the elastically deformable sealing element. The friction and/or wear element ensures high abrasion resistance of the sealing device. The elastically deformable sealing element enables the sealing effect of the sealing device to be maintained even when the cam ring moves relative to the support ring during the adjustment of the variable displacement pump. As a particularly advantageous option, sealing gaps between the cam ring and the support ring can be sealed off in a variable manner by means of the sealing device according to the invention.

Further advantages, features and details of the invention will become apparent from the following description, in which various illustrative embodiments are described in detail with reference to the drawing, in which:

FIG. 1 shows two housing parts with a sealing device in cross section;

FIG. 2 shows a perspective view of the sealing device from FIG. 1;

FIG. 3 shows a perspective view of a friction and/or wear element according to the invention;

FIG. 4 shows a perspective view of a sealing device having the friction and/or wear element from FIG. 3, and

FIG. 5 shows an exploded detail view of a cam ring of a variable displacement pump having the sealing device from FIG. 4.

FIG. 1 shows a technical device 1 having a first housing part 4 and a second housing part 5 in cross section in greatly simplified form. The second housing part 5 has the shape of a flat plate, which is spaced apart slightly from the first housing part 4. The first housing part 4 surrounds a longitudinal groove 8, in which a sealing device 10 is partially accommodated.

The sealing device 10 illustrated in perspective in FIG. 2 comprises a friction and/or wear element 11 composed of a relatively dimensionally stable material, in particular a fluoroelastomer. The friction and/or wear element 11 has a rectangular cross section. The sealing element 12 is embodied as an O-ring bead with a circular cross section and is elastically deformable.

In the installed state of the sealing device 10 in FIG. 1, it can be seen that the sealing element 12 has been elastically deformed, resulting in a preloading force, by means of which the friction and/or wear element 11 is held in close contact with the second housing part 5.

FIG. 3 shows a friction and/or wear element 21 according to the invention in perspective. The friction and/or wear element 21 has an elongate main body 24 with a rectangular cross section. The elongate main body 24 has two angled ends 26, 27, which are each angled at a right angle to the elongate main body 24.

The angled ends 26, 27 likewise have a rectangular cross section. The two mutually facing inner surfaces 28, 29 of the angled ends 26, 27 of the elongate main body 24 form contact surfaces for a sealing element.

In FIG. 4, the friction and/or wear element 21 is illustrated with a sealing element 22. Together with the friction and/or wear element 21, the sealing element 22 forms a sealing device 20 according to the invention. The sealing element 22 is embodied as an O-ring bead with a circular cross section. The ends 31, 32 of the sealing element 22 rest partially on the inner surfaces 28, 29 of the angled ends 26, 27 of the friction and/or wear element 21. The sealing device 20 can also be inserted into the longitudinal groove 8 of the device 1 from FIG. 1.

FIG. 5 shows a detail view of the cam ring 40 of a variable displacement pump in perspective. On the outside, the cam ring 40 is provided with a longitudinal groove 44, which serves to accommodate the sealing device 20. In this arrangement, the sealing device 20 is inserted into the longitudinal groove 44 in such a way that the angled ends of the friction and/or wear element 21 illustrated fully in FIGS. 3 and 4 partially encompass the ends 32, 31 of the sealing element 22.

The variable displacement pump comprises a cam ring and a support ring. The cam ring is arranged adjustably within the support ring, which is also referred to as a spacer ring. In turn, a rotor is driven within the cam ring, e.g. by a drive shaft.

The variable displacement pump is a hydraulic pump, which is embodied as a vane pump. Radially extending slots, in which vanes are guided in a radial direction, are provided in the rotor. The vanes rest by means of the radially outer ends thereof on a cam contour, which is provided on the inside of the cam ring.

When the rotor rotates, there is an increase in volume in the region of a suction space between the rotor and the cam ring, causing a hydraulic medium to be drawn in via an intake opening. At the same time, there is a decrease in volume in a pressure region between the rotor and the cam ring, causing the hydraulic medium to be pumped into a kidney-shaped pressure port.

The delivery rate of the variable displacement pump can be varied by adjusting the cam ring relative to the rotor within the support ring or spacer ring. During adjustment, the cam ring performs a pivoting motion around a pivot pin, which is arranged in corresponding depressions between the cam ring and the support ring.

The cam ring is preloaded by a spring, which is arranged in a recess. A total of three variable pressure spaces is formed between the cam ring and the spacer ring, these spaces being sealed off from one another by sealing devices and the pivot pin. In the case of the sealing devices, it is the same sealing device as that illustrated in FIGS. 3 to 5.

The sealing devices are each arranged in a longitudinal groove, which is provided in the cam ring. The friction and/or wear elements of the sealing devices are relatively dimensionally stable and are each held in close contact with the support ring by an elastically deformable sealing element.

LIST OF REFERENCE SIGNS

-   1 device -   4 first housing part -   5 second housing part -   8 longitudinal groove -   10 sealing device -   11 friction and/or wear element -   12 sealing element -   20 sealing device -   21 friction and/or wear element -   22 sealing element -   24 elongate main body -   26 end -   27 end -   28 inner surface -   29 inner surface -   31 end -   32 end -   40 cam ring -   44 longitudinal groove 

What is claimed is:
 1. A sealing device comprising: a relatively dimensionally stable, elongate friction and/or wear element (11, 21); an elastically deformable elongate sealing element (12, 22) which rests lengthwise on the friction and/or wear element (11, 21); and wherein the friction and/or wear element (21) encompasses the sealing element (22) at the ends of the friction and/or wear element.
 2. The sealing device of claim 1, wherein the friction and/or wear element (21) is of substantially U-shaped design.
 3. The sealing device of claim 1, wherein the friction and/or wear element (21) has an elongate main body (24) with two angled ends (26, 27).
 4. The sealing device of claim 3, wherein the elongate main body (24) has a substantially rectangular cross section.
 5. The sealing device of claim 3, wherein the angled ends (26, 27) each have a substantially rectangular cross section.
 6. The sealing device of claim 3, wherein the ends (26, 27) of the friction and/or wear element (21) are each angled at a right angle to the elongate main body (24).
 7. The sealing device of claim 1, wherein the sealing element (22) is connected in a captive manner to the friction and/or wear element (21).
 8. The sealing device of claim 1, wherein the sealing element (22) rests by means of the ends (31, 32) thereof on the angled ends (26, 27) of the friction and/or wear element (21).
 9. The sealing device of claim 1, wherein the sealing element (22) is preloaded against the friction and/or wear element (21) in the longitudinal direction.
 10. The sealing device of claim 1, wherein the sealing element (22) is connected materially and/or positively to the friction and/or wear element (21) at the ends of the sealing element.
 11. The sealing device of claim 1, wherein the friction and/or wear element (21) is embodied as a sealing strip.
 12. The sealing device of claim 1, wherein the sealing element (22) is embodied as an O-ring bead.
 13. A friction and/or wear element (21) for a sealing device (20) comprising: a relatively dimensionally stable, elongate friction body for supporting an elastically deformable elongate sealing element (22); and the body including ends for encompassing the sealing element (22).
 14. A cam ring (40) having a groove (44) in which a sealing device (20) as claimed in claim 1 is arranged.
 15. A variable displacement pump having a cam ring which can be moved in order to adjust the stroke of the variable displacement pump and which has a groove, and having a support ring, and a sealing device as claimed in claim 1 arranged in the groove in such a way that the friction and/or wear element (21) is held in contact with the support ring by a preload of the elastically deformable sealing element (22). 